Long jump/triple jump pits (“jump pits”) have been known and used in track and field for some time. The jump pit itself is typically a rectangular sand pit with a runway leading up to one of the short sides of the rectangle. The jump pit must hold sufficient quantities of sand to cushion an athlete's landing following a jump. The sand in the jump pit must be protected from ambient and environmental conditions and contingencies, such as weather elements and animals. The sand must be kept dry and clean to preserve its integrity and to protect the athletes, and it must be free of debris. Therefore, it is preferable to provide a jump pit with a perimeter containment wall that includes reasonably well-fitting cover that minimizes gaps where the cover contacts the containment wall of the jump pit. Such covers can be made of a variety of materials, including wood, fabric (such as a vinyl-coated mesh fabric) or metal, such as aluminum sheeting or panels.
There are a number of steps involved in building a custom form assembly for creating a jump pit, and there are many difficulties to overcome before achieving the end result of a sand pit of predetermined size that will receive a standard cover without gaps where the cover contacts the periphery of the jump pit. Most jump pits are created by digging a recess in the ground having dimensions slightly larger than the desired dimension of the jump pit, building a form assembly about the perimeter of the recess that is dimensioned so as to provide a perimeter containment wall in which the interior dimensions of the wall correspond to the desired exterior dimensions of the jump pit. The containment wall is typically formed of a moldable forming composition, such as a cementitious material (e.g., concrete), a polymer concrete or a similar material. The form will typically comprise interior and exterior frame members that are secured in place a predetermined distance apart from one another and that are structured to laterally contain the moldable forming composition used to form the wall while the moldable forming composition cures. The interior and exterior form members are commonly formed of wood. Rebar or other similar internal structural elements may be positioned between the interior and exterior form members to increase the structural strength of the wall. The interior and exterior form members may also be coupled together using metal wire or mechanical fasteners to prevent movement of one form member away from the other form member.
It is common to form a ledge along the upper, interior corner of the wall that is dimensioned to receive the cover. In one embodiment, the depth of the ledge corresponds approximately to the thickness of the cover and two (2) times the width of the ledge plus the width of the jump pit corresponds approximately to the width of the cover. The ledge is sometimes formed using an L-shaped channel, which, in one embodiment, is formed of aluminum.
One difficulty often encountered when building the form is positioning and securing each of the components correctly in place and maintaining such positioning when pouring the moldable forming composition into the form. As such, onsite forms result in jump pits of varying dimensions, due to slight variations in sizes of custom-built components, shifting of form assembly components during the pouring and curing of the moldable forming composition. In particular, it can be difficult to form the ledge so that the ledge is level around the entire perimeter. This difficulty arises in part due to problems associated with positioning and securing the L-shaped channel correctly in place and maintaining such positioning as the moldable forming composition is poured into the form, as the moldable forming composition has a tendency to urge the channel upwards and laterally away from the form. These variations, among other things, can result in a jump pit of uneven dimensions that requires fitting with a custom cover.
A further challenge to creating a jump pit using a custom built onsite assembly form is the difficulty in removing the form components after the moldable forming composition is poured and cured. This can be a labor intensive, time consuming process that can result in components being broken in order to dislodge them from the containment wall formed by the moldable forming composition.